The present invention relates to switching devices, and more specifically, to metal gate transistors.
The term high-k dielectric refers to a material with a high dielectric constant (k) (as compared to silicon dioxide) used in semiconductor manufacturing processes which replaces the silicon dioxide gate dielectric. The implementation of high-k gate dielectrics is one of several strategies developed to allow further miniaturization of microelectronic components.
Silicon dioxide has been used as a gate oxide material for decades. As transistors have decreased in size, the thickness of the silicon dioxide gate dielectric has steadily decreased to increase the gate capacitance and thereby drive current and device performance. As the thickness scales below 2 nm, leakage currents due to tunneling increase drastically, leading to unwieldy power consumption and reduced device reliability. Replacing the silicon dioxide gate dielectric with a high-k material allows increased gate capacitance without the concomitant leakage effects.